Tuesday, September 24, 2013

Aufs included in Ubuntu kernels is broken, what a surprise. In addition it has been dropped from newer kernels with claims that overlayfs does exactly same thing. It doesn't and everyone knows it except that one developer who decided it does and can't admit he made mistake. It seems aufs (and overlayfs) in Ubuntu is not really supposed to be used but only be part of install process. If so you guys shouldn't include it outside installer.. WontFix you too.

Sunday, September 22, 2013

Some time ago I purchased external 3TB USB 3.0 hard disks, TrekStor DataStation maxi light 3TB to be exact. It seem disk models and manufactures used by TrekStor vary, which is no surprise. Therefore I have externally identical disk enclosures with three different models of disks due making three separate purchases over few months.

Wednesday, September 18, 2013

Depending on why you're encrypting your SSDs it might be acceptable to enable TRIM (aka discard). With this configuration observing raw content on SSDs will reveal which blocks are used and which aren't. Doesn't matter for me, but might not be same for you.

My original plan was to boot from ZFS, but combining it with encryption and especially with mirrored disks turned out to be too troublesome. Yes, I did get it working and booting, but resulting configuration required manual fixing each time new kernel was installed. And don't even think about doing upgrade to next Ubuntu version.

After realizing that LSI SAS1078 based controller wouldn't do what I want I ended up purchasing card from eBay, 65€ including shipping for unused, new in box Dell PERC H310. Prices are bit higher than I like, but this was acceptable knowing it will do exactly what I need. Despite trying hard card will still show up as DELL after making these changes but it's in IT-mode and accepts generic LSI firmware.

Wednesday, September 11, 2013

I wanted to use Fujitsu OEM (D2516, "LSI Logic MegaRAID SAS PCI Express(TM) ROMB") of LSI MegaRAID 8708ELP in JBOD mode, which apparently is not possible. Out of MegaRAID products only 9240-4i and 9240-8i support true JBOD. Also 9260 and 9280 series can apparently do it via MegaCLI which is another beast to master. Rest of models can only do single disk RAID0 which isn't the same thing.

Tuesday, September 10, 2013

For whatever reason after updating my Intel X25-M G2 SSD to latest firmware (dated 2011) option to do secure erase disappeared. Yes, I know all about tricks of hot plugging disks etc. Secure erasing another identical X25-M G2 on same PC visible as /dev/sdb works fine. One with latest firmware simply no longer supports it which is also confirmed by hdparm -I.